Simultaneous fusing multipolar protector



Oct. 18, 1966 I A. P. RODRIGUEZ 3,280,283

SIMULTANEOUS FUSING MULTIPOLAR PROTECTOR Filed June 20, 1963 mvewrok ARTURO PRZ ROM/60H United States Patent 3,280,283 SIMULTANEOUS FUSING MULTIPOLAR PROTECTOR Arturo Prez Rodriguez, Calle General Moscardo 2, Madrid, Spain Filed June 20, 1963, Ser. No. 289,446 Claims priority, application Spain, Dec. 6, 1962, 283,160 3 Claims. (Cl. 200-120) This invention relates to a novel device for protecting multipolar electrical apparatus.

A primary object of the invention, therefore, is to provide a novel means for protecting multipolar electrical apparatus.

Other objects of the invention will in part be obvious and Will in part appear hereinafter.

For fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a perspective view of a device of this invention; and

FIG. 2 is an enlarged, fragmentary, perspective view of the device of FIG. 1 in vertical section on the lines a-b of FIG. 1.

As shown in the illustrative drawing, the protector device of this invention comprises a body 1 of some suitable insulating material e.g. electric porcelain, having thereon as many pairs of metal terminals as there are phases 2.

For each phase, body 1 has a pair of cavities 3, the inner ends or concurrent vertices of which are in the center of the body, where there is a clearly defined cavity 5.

Fuse wires 4 join each pair of terminals for the same phase. Most of the length of these wires is inside their respective cavities 3 which are filled with absorbent materials such as are normally used in fuses. Only in cavity or space 5 are the fuse wires together in a single enclosed space for a length and at a distance suited to the applied voltage and current levels to be carried by the wires. Since the enclosed space 5 is the most thermally insulated, the system is fused at this point by bringing the wires into closer proximity through a reduction in section of the insulating body through which the wires pass. The fuse is implemented by the fact that the amount of heat generated ,is proportionate to the number of phases.

When there is an overload in one phase, the portion of the wire of that phase in space 5 fuses or burns out at this point. Due to the relatively close distance between the Wires of the several phases in this space and the absence of absorbent material between them, an arc is created, thus shorting out all of the wires within space 5 and opening the circuit in all phases. The gases produced are absorbed by the absorbent materials defining the cavities.

For the purposes of illustrating the invention, the device shown in FIG. 1 is at approximately natural size, being adapted for five hundred volts and ten amps.

Having thus described the invention, what is claimed is:

1. A device for protecting multipolar electrical apparatus comprising a body formed of insulating material, said body having on opposed surfaces thereof a plurality of metal terminals,

a plurality of cavities defined by said insulating material extending from each said terminal and through said body to another said terminal, each of said cavities being adapted to confine a fuse strip in spaced relationship from another fuse strip in said body, said cavities extending through said body inwardly with respect to one another and converging to define at some point within said body a common cavity of reduced area wherein said fuse strips are in closest proximity Within said body, the dimensions of said common cavity being adapted with respect to the applied voltage and current of said electrical apparatus, to provide a fuse point whereby an overload in one phase may short out all of the fuse strips Within said common cavity.

2. A device as defined in claim 1 including a fuse strip extending through each of a plurality of said cavities, each of said fuse strips connecting a pair of terminals on opposed surfaces of said body.

3. A device as defined in claim 2 wherein each of said cavities adapted to contain said fuse strips is substantially conical and the concurrent vertices of said cavities define said common cavity at a point substantially in the center of said body.

References Cited by the Examiner UNITED STATES PATENTS 1,239,876 9/1917 Burnham 317-46 MILTON O. HIRSHFIELD, Primary Examiner.

SAMUEL BERNSTEIN, Examiner.

R. V. LUPO, Assistant Examiner. 

1. A DEVICE FOR PROTECTING MULTIPOLAR ELECTRICAL APPARATUS COMPRISING A BODY FORMED OF INSULATING MATERIAL, SAID BODY HAVING ON OPPOSED SURFACES THEREOF A PLURALITY OF METAL TERMINALS, A PLURALITY OF CAVITIES DEFINED BY SAID INSULATING MATERIAL EXTENDING FROM EACH TERMINAL AND THROUGH SAID BODY TO ANOTHER SAID TERMINAL, EACH OF SAID CAVITIES BEING ADAPTED TO CONFINE A FUSE STRIP IN SPACED RELATIONSHIP FROM ANOTHER FUSE STRIP IN SAID BODY, SAID CAVITIES EXTENDING THROUGH SAID BODY INWARDLY WITH RESPECT TO ONE ANOTHER AND CONVERGING TO DEFINE AT SOME POINT WITHIN SAID BODY A COMMON CAVITY OF REDUCED AREA WHEREIN SAID FUSE STRIPS ARE IN CLOSEST PROXIMITY WITHIN SAID BODY, THE DIMENSIONS OF SAID 